Update samples to use icr.io/appcafe and added image list

[BradleyMayo]

1. Cleaned up the start of the overall readme
2. Removed reference to outdated helm chart
3. Added image list similar to the one from liberty https://github.com/OpenLiberty/ci.docker/blob/main/docs/icr-images.md
4. Updated samples to use icr.io/appcafe instead of ibmcom
5. Updated build_all.sh script to pull from icr.io/appcafe instead of ibmcom